The seats in the conventional car in general are provided with seat and back cushions for the users' sitting and leaning thereon so that the cushions feel soft and comfortable. However the comfortable feeling of these cushions chiefly depends on the status of back cushion coinciding with the human body spine when the back cushion contacts the human body spine. Since the human body spine supports the whole weight of the human body and head, if one's spine is in a poor state of bending for a long time, he will experience lumbago, back pain and sore head and neck.
The conventional cushion (such as the back cushion) is composed of a soft sponge adhered onto a piece of fixed hard plate. So far as this fixed cushion is concerned, when the human body spine leans thereon, the spine will always have to meet with the established fixed pattern thereof, and then will be subject to the restraint of said pattern, so the user will feel uncomfortable and his health will be unfavorably affected (such as suffering herniation of interverbral disc).
In addition, the plate surface of the conventional cushion (such as a back cushion) is a flat plate without any arcuate shaping, so when one's body leans on the flat plate cushion, the arcuate part of his spine cannot coincide with the plate surface, and his spine cannot be properly supported. Therefore, so far as those who have to stay in the car for a long time are concerned, the cushion becomes very uncomfortable; additionally, since the plate surface of a conventional cushion is airtight, the user's back tends to sweat so as to add to his discomforture.